On January 12, the T+L combined shield support independently designed and developed by the Production Service Center of Shendong Coal was officially put into operation. It successfully tackled the core problem of support in the triangular area during the withdrawal of the longwall mining face underground, achieving multiple breakthroughs in safety, efficiency and cost control.

It was understood that support in the triangular area had long been a high-risk and difficult step in the hydraulic support withdrawal during the equipment relocation of the longwall mining face. The traditional process required 6 operators to immediately move sleepers and round timbers for triangular area support after the withdrawal of supports. A single operation took about 20 minutes. It not only brought high labor intensity, but also posed safety risks covering mesh tearing and gangue leakage in the triangular area. Even the subsequent adoption of sequential withdrawal process with multiple shield supports still needed auxiliary support from non-recyclable materials including sleepers, leading to accumulated material loss. In addition, the shield supports pulled by winches were prone to tilting, resulting in insufficient safety and stability. Labor and material costs were thus difficult to control effectively.

To address the above risks and hidden dangers, the Production Service Center of Shendong Coal independently developed the T+L combined shield support based on operation space and regional requirements. With an emulsion pump as the power source, the support was designed as an integral frame support group consisting of triple shield supports and T-shaped supports, realizing the self-moving function of micro-supports. All operations were completed remotely through wireless remote control. It could accurately control the pushing, lifting and lowering of supports, ensuring stable arrival at designated support positions. Meanwhile, the reasonable support layout greatly improved the stress stability of supports. It could effectively tackle structural shaking and deformation under complex working conditions.

After the application of the new support, the support operation only required 1 operator and could be completed within 5 minutes, representing a significant efficiency improvement compared with the traditional process. It completely replaced timber support, greatly reducing material and labor costs. It effectively eliminated safety hazards such as roof falling and rope breaking or chain flying. Accurate support positioning also reduced floor-excavation errors, further ensuring equipment operation safety and operation accuracy. It comprehensively improved the equipment level for mining face relocation.